The invention relates to a refrigerator for domestic use as well as to a refrigerator for professional use such as in a restaurant, hotel and similar.
It is known that ethylene is a gas that affects produce ripening. In particular, as known, ethylene gas is a natural hormone which is released by produce at different rates, depending upon produce types. Ethylene production rates can increase with produce maturity at harvest, physical injuries (cutting, scratching, bruising, etc), disease incidence, increased temperatures (e.g. up to about 30° C.) and water stress (e.g. resulting from low relative humidity).
Ethylene is physiologically active, even at extremely low concentrations (e.g. 0.1 ppm), for produce ripening, which is a natural phenomenon, but it may also cause the decay of produce.
US 2004/0210099 discloses a method for maintaining the freshness of, or conversely controlling the maturation of, plants or perishables such as fruits, vegetables, and flowers, by controlling the concentration of ethylene gas by use of an ethylene gas adsorbent containing an alcohol extract solution of raw bamboo and a filter having held thereon the alcohol extract solution.
U.S. Pat. No. 5,451,248 discloses a system for controlling the atmosphere of a container for use in the storage and/or transportation of perishable goods which includes adsorption apparatus for the selective absorption in whole or in part and in a predetermined order of any water vapor, carbon dioxide, oxygen or ethylene contained within the atmosphere, a blower for urging the atmosphere to the absorption apparatus, and a conduiting for returning the controlled atmosphere to the container.
The applicant observes that the above documents relate to the control of the atmosphere in industrial containers for use in storage and/or transportation of perishable goods in industrial applications. In these applications, the size of the containers, the amount of perishable goods and the amount of gas/vapour under control are very large and not comparable with those of domestic applications. Differently from industrial containers, domestic and professional refrigerators are designed to store different types of food (meat, fish, dairy products, fruits, vegetables). The herein solution to control the ethylene concentration is applied only to a specific section of the domestic/professional refrigerator (e.g. drawer). Another difference between industrial containers and domestic/professional refrigerators is the final user. In the first case the user is very skilled in food preservation issues and knows well the connected processes (e.g. ripening, rotting). In the second case the user can be completely or partially unaware (e.g. housewife) or can have limited knowledge of the matter (e.g. cook). This means that in domestic/professional applications much more complexity is required in terms of control to guarantee a satisfactory function.
US 2011/0204762 discloses a domestic refrigerator comprising a sliding drawer positioned in the refrigerated compartment and utility modules sized to be positioned within the storage chamber of the sliding drawer. In an embodiment, the utility modules comprise a housing with a vented compartment defined therein, which is sized to receive a sachet containing an ethylene absorbing agent to eliminate ethylene generated by food items stored in the drawer, thereby helping to preserve food items stored in the drawer. An elapsed time indicator is provided, which provides an indication of how long the sachet has been used. When the sachet is replaced, a new indicator is provided.
It is an object of the invention to improve produce ripening management in a domestic/professional refrigerator.
The Applicant has found that this object can be achieved by a domestic/professional refrigerator comprising a produce ripening control system with an ethylene absorber adapted to selectively operate in an absorption mode and in a desorption mode. A recirculation circuit is configured to recirculate air from a storage chamber, via the ethylene absorber and back into the storage chamber. A control unit is configured to selectively operate the absorber either in the absorption mode or in the desorption mode. When the absorber operates in absorption mode, ethylene is absorbed and a first produce ripening effect (i.e. produce ripening delay) is obtained while, when the absorber operates in desorption mode, ethylene is desorbed and a second, opposite, ripening effect (i.e. produce ripening acceleration) is obtained. This advantageously provides a user with the possibility of selectively treating the produce stored in his/her refrigerator depending on current needs, thereby improving the versatility and flexibility of the domestic/professional refrigerator. In addition, it advantageously enables to fully exploit adsorbing/desorbing capabilities of ethylene absorber, thereby improving the efficiency of the produce ripening control system. Produce ripening management at domestic/professional level is thus improved.
In a first aspect the present invention thus relates to a domestic/professional refrigerator comprising a storage chamber for produce storage and a produce ripening control system, the produce ripening control system comprising:                an ethylene absorber adapted to operate in absorption mode in a first status and in desorption mode in a second status;        a recirculation circuit configured to fluidly connect the absorber with the storage chamber and to draw air from the storage chamber, to flow the drawn air through the absorber and to return it into the storage chamber; and        a control unit configured to selectively operate the absorber either in the absorption mode for ethylene absorption or in the desorption mode for ethylene desorption.        
Preferably, the absorber is adapted to operate in absorption mode at a temperature T1 and to operate in desorption mode at a temperature T2 higher than temperature T1.
Preferably, the produce ripening control system further comprises a heater thermally coupled to the absorber, the control unit being configured to control the heater to operate the absorber at said temperature T1 or at said temperature T2.
In a preferred embodiment, said storage chamber defines a first storage chamber, and the refrigerator further comprises a second storage chamber for produce storage, the recirculation circuit being configured to fluidly connect the second storage chamber with the absorber and to draw air from the second storage chamber, to flow the drawn air through the absorber and to return it into the second storage chamber.
Preferably, the recirculation circuit is configured to fluidly connect the second storage chamber with the absorber bypassing the first storage chamber.
Preferably, the recirculation circuit is configured to fluidly connect the first storage chamber with the absorber bypassing the second storage chamber.
Preferably, the control unit is configured to operate the recirculation circuit so that in the absorption mode of the absorber the air is recirculated through the first storage chamber bypassing the second storage chamber, while in the desorption mode of the absorber the air is recirculated through the second storage chamber bypassing the first storage chamber.
Preferably, the recirculation circuit comprises air flow switching elements arranged so that the air can be recirculated into the recirculation circuit bypassing either the first storage chamber or the second storage chamber.
Preferably, the control unit is configured to operate the air flow switching elements so that in the absorption mode of the absorber the air is recirculated through the first storage chamber bypassing the second storage chamber, while in the desorption mode of the absorber the air is recirculated through the second storage chamber bypassing the first storage chamber.
The recirculation circuit could comprise a suction or blowing element configured to re-circulate air along the recirculation circuit.
Preferably, the produce ripening control system comprises a first ethylene sensor associated with the first storage chamber to sense ethylene concentration within the first storage chamber, the control unit being configured to operate the absorber and the recirculation circuit according to data received by the first ethylene sensor.
Preferably, the produce ripening control system comprises a second ethylene sensor associated with the second storage chamber to sense ethylene concentration within the second storage chamber, the control unit being configured to operate the absorber and the recirculation circuit according to data received by the second ethylene sensor.
In a preferred embodiment, the control unit is configured to operate the absorber and the recirculation circuit according to information relating to produce type stored into the first storage chamber and/or the possible second storage chamber.
In a preferred embodiment, the domestic/professional refrigerator further comprises a user interface for receiving user inputs, the control unit being configured to operate the absorber and the recirculation circuit depending on the user inputs.
Preferably, the produce type stored into the first storage chamber and/or the possible second storage chamber is received as user input via said user interface.
In a preferred embodiment, the produce ripening control system further comprises a database of produce preservation/ripening information, the control unit being configured to operate the absorber and the recirculation circuit depending on the information stored into the database.
Preferably, the information relating to the produce type stored into the first storage chamber and/or the possible second storage chamber, are retrieved from said database.
In a preferred embodiment, the produce ripening control system comprises a first temperature sensor associated with the first storage chamber to sense the temperature within the first storage chamber, the control unit being configured to adjust the temperature within the first storage chamber in cooperation with the first temperature sensor and according to information relating to produce type stored into the first storage chamber.
In a preferred embodiment, the produce ripening control system comprises a second temperature sensor associated with the second storage chamber to sense the temperature within the second storage chamber, the control unit being configured to adjust the temperature within the second storage chamber in cooperation with the second temperature sensor and according to information relating to produce type stored into the second storage chamber.
Preferably, the first storage chamber and/or the possible second storage chamber is suitably sealed.
Preferably, the first storage chamber and/or the possible second storage chamber comprises a sealed opening/closing door.
Preferably, the first storage chamber and/or the possible second storage chamber is defined by a drawer.
Preferably, the drawer comprises a gasket to seal it in a closed position.